The great thing about Halon, other than it does not leave a mess is, that the amount needed to suppress a fire it well below the level of immediate issues for the people.
I did not know about the hang upside down thing, and it is a good thing to know. But looking online, I do not see any mention of this. Do you have an actual source other that the medic (what qualifications) said so?
[quote]This is because exposures to concentrations of 7% for more than 15 minutes can be very dangerous. The risk is minor when exposed to Halon in the 5-7% range as no noticeable effect can occur. However, at levels between 7% to 10%, the likelihood of toxicity increases significantly. That’s why, in places where Halon is still used and needed to be used, it is highly recommended that operators evacuate the space before proceeding.[/quote]